In this paper the authors describe the outcomes of infants who were in their Sugar Babies study, when they reached 2 years of age. The infants had Bayley scales of infant development version 3 performed, as well as tests of executive function and neurological exams.

To recap, the Sugar Babies study took infants at risk of hypoglycemia, and when the blood sugar was below 2.6 mmol/L (47 mg/dl) they were randomized to either get dextrose gel, or placebo. They could get treated more than once if necessary, and if the blood glucose fell to more severe levels the received standard therapy. 237 babies were in the original study, 78% of them returned for follow-up.

The babies of course, as mentioned, all had risk factors for hypoglycemia, so there were 40% whose mothers were diabetic, 1/3 were late preterms, 16% SGA, 8% LGA. The outcomes were not different between the two groups, but they were not very reassuring. 34% of the infants had a Bayley cognitive or language composite less than 85, (1 SD below the standardized mean value of 100, which we know is not the mean of the general New Zealand population) The mean language and cognitive composite scores of the subjects were between 94 and 96, Full term controls in a recent Australian study had means of 108 to 109.

So these babies, in both groups look like they did substantially worse on the Bayley test than you might expect. There were also a few babies with other problems, including 9 with seizures, and their executive function scores were abnormal also. Is this because the risk factors that they had select a group of babies who are higher risk? Is it because mild hypoglycemia, even if you treat with a rapidly effective intervention, such as the dextrose gel, has a direct adverse effect on the newborn brain? We know that infants who are small for gestational age, and late preterm infants are at risk for developmental delay, but there seems to be remarkably little data about the risks of infants of diabetic mothers.

It certainly looks like being a newborn infant in a group at risk for hypoglycemia, who then has a blood sugar under 2.6 is a risk factor for developmental delay and for executive function disturbances.